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Tips
Tips

TR4/4A Replacing front brake hoses

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RJS

RJS

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Does anyone have any tips for performing this job? This will be my first time working on brake hoses. I'm only doing the front calipers.

I'm soaking the nuts in PB Blaster for several days and plan to buy some flare nut wrenches. My biggest fear is these will be really tough to get off and ruining the metal pipes when removing the hoses. I really don't want to go down that road.

When installing the new hoses:
-should I prepare the threads with anything (i.e. locktite or teflon thread tape)?
-how tight do I want to tighten the connections? In my earlier days, I had a habit of ruining a lot of fasteners by tightening them within an inch of their life
-once installed, do I need to bleed all four corners or can I only bleed the front calipers?

The reason I am doing this is because the car pulls to right just as I apply the brakes. I tested the calipers and observed the following:
Right caliper: I can relieve both caliper pistons rather easily using a pair of channel lock pliers
Left caliper: it is very hard to depress either caliper piston. And after I depress the first caliper piston, it pushes back out when I depress the other piston in the same caliper.

So, I am fairly convinced I have a blocked or swollen brake hose.

Thanks all

Bob
 
1. Nothing on the threads. The sealing occurs on the tapers.
2. How tight?? Tight enough so it don't leak or come loose.
3. Generally not necessary to bleed all four, unless you want to replace with all new fluid. Just do one hose at a time. Try to lose as little fluid as possible and bleeding will be easier.
 
As I recall, there is a sequence involved -- i.e. which end of the hose you do first matters. I'm thinking you undo the union connection first, then proceed to the connection at the caliper -- otherwise you'll be twisting the hose as you undo the caliper end.

Assembly, as they say, is reverse of the above.
 
Make a stick and compress the brake pedal just a little 1/4" to 1/2" will line the Master Cylinder cups to prevent fluid from draining at open caliper, then you only have a short bleed at caliper.
 
Also a little plastic wrap under the lid helps too.
 
Cut the old cable and use a ring-spanner or a deep 6-point socket perhaps, so you dont round off the fittings trying the get them undone.

I put Teflon tape on but not to seal them. Just so they undo easily next time.

Dont worry too much about the metal pipes. Its not very hard to make new ones of these.
 
If the nut or the female pipe end seem at all stubborn, judicious use of a propane torch will help free things up. It doesn't take much. At worst, too much heat will sometimes pop the rubber hose out of the fitting, but it's not a problem since you're replacing the hoses. However you do it, good flare nut wrenches are a must, IMO!
 
Most likely you'll be fine; just be sure to hold the flats on the hose (not the nut that secures it to the tab) while loosening the nut on the line.

But if the line does start to twist, just replace it! They don't last forever anyway, and the last thing you want to do is take a chance on it failing during a panic stop. Moss sells a nice set in Cunifer but unfortunately not the individual pieces, so I just bought the set and am slowly replacing all the hard lines. The Cunifer bends much easier than the original plated steel, and is more resistant to corrosion.

Install the caliper end first. Then when you tighten the nut that holds the other end to the frame tab, be sure to turn the hose so it doesn't rub against anything even with the steering turned all the way right or left. It needs to make kind of a funny curve to clear the upper ball joint, but not get kinked under any conditions. Last step is to install and tighten the flare nut.

I've not tried Andy's torch trick, but note that brake fluid is flammable and will burn with enough encouragement. I'm not saying don't do it, just don't panic when the flame gets larger than you expected :smile:
 
Hi

Update. I replaced the front brake hoses today. Thanks to your help above, it went like clockwork. I think the biggest secret was soaking the nuts twice a day with PB Blaster for 6 days. Nuts came right apart using a 9/16" flare nut wrench. Biggest pain was the brake fluid leaking from the hard lines for the couple of minutes it took me to get the new hoses in place. Next time I'll try the suggestion above about depressing the brake pedal 1/2".

I bled the brakes again. Pedal feels great and braking is straight and true. No more pulling/ jerking to the right when I apply the brakes.

The flared unions must seal real well. I didn't crank the torque too hard. Just a nice firm snug, based on feel - and they hold the pressure just fine.

Thanks

Bob
PS: I did cut the old hoses open to inspect. While the diameter of the hole was quite small, I did not see any visible blockage or swelling. Either way, it was obviously a bad hose since brakes feel and perform like new again.
 
RJS said:
...Biggest pain was the brake fluid leaking from the hard lines for the couple of minutes it took me to get the new hoses in place...
Click to expand...

Oh yeah (now he tells me) I cut the finger off a latex glove and slip that over the line, then use a twisty (like from a loaf of bread) to clamp it on the pipe. Stops the bleeding (or at least the hemorrhaging) whilst I complete the operation.
 
Ha ha, thanks Geo. Good tip that I will remember next time. It wasn't that bad. I stuffed paper towels up against it which soaked up the fluid so it didn't get everywhere

Bob
 
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